In a significant victory for gay rights, a federal appeals court in Chicago ruled Tuesday that the 1964 Civil Rights Act protects gay workers from job discrimination, expanding workplace protections in the landmark law to include sexual orientation.

The decision by the United States Court of Appeals for the Seventh Circuit, the highest federal court yet to grant such employment protections, raises the chances that the politically charged issue may ultimately be resolved by the Supreme Court. While an appeal is not expected in this case, another appellate court, in Georgia, last month reached the opposite conclusion, saying that the law does not prohibit discrimination at work for gay employees.

The ruling on Tuesday comes as gay rights advocates have voiced concern about the potential rollback of protections under President Trump. While the Supreme Court legalized same-sex marriage, many other legal protections, including in employment and housing, have not been extended at all levels to gay people.

In the decision on Tuesday, the judges ruled by an 8-to-3 vote that the civil rights law, which already prohibits discrimination on a variety of factors, also includes protections based on sexual orientation. They concluded that such discrimination was no different from a form of sex discrimination, which the law prohibits. Five of the eight judges in the majority were appointed by Republican presidents.

The case stems from a lawsuit by Kimberly Hively, an Indiana teacher who has alleged that she was fired from Ivy Tech Community College because she is a lesbian. She applied to six full-time jobs at the school in South Bend, Ind., that she did not get, and she was let go from her part-time position there in 2014.

The community college denies that she was discriminated against because of her sexual orientation.

“Hively’s claim is no different from the claims brought by women who were rejected for jobs in traditionally male workplaces, such as fire departments, construction and policing,” the court’s chief judge, Diane P. Wood, wrote in the opinion. “Ivy Tech is disadvantaging her because she is a woman.”

The court did not rule on Ms. Hively’s specific anti-discrimination lawsuit. But the ruling allows for Ms. Hively’s employment case to proceed. A lower court had dismissed her case, ruling that the Civil Rights Act did not include sexual orientation protections.

Ms. Hively, who represented herself in the lower court because she said no lawyer thought she would win, said late on Tuesday that she was still processing the significance of the ruling.

“I wasn’t doing it just for me, but for anyone who was going to be bullied in a job for who they decided to love,” she said in an interview.

Greg Nevins, the employment fairness program director for Lambda Legal, which represented Ms. Hively, called the ruling a “tremendous victory.” He said the Seventh Circuit’s approach to the Civil Rights Act was a momentous shift from past cases.

“The problem with the old decisions was a focus on the words that were not in the statute — ‘We don’t see sexual orientation in the statute, so you lose’ — instead of what is in it: sex discrimination,” Mr. Nevins said in an interview.

An official at Ivy Tech said on Tuesday night that it “respects and appreciates” the ruling and does not plan to appeal it to the Supreme Court. “The college denies that it discriminated against the plaintiff on the basis of her sex or sexual orientation and will defend the plaintiff’s claims on the merits in the trial court,” said the official, Jeff Fanter, the senior vice president for communication and marketing at Ivy Tech.

Lawyers with the firm Barnes & Thornburg, which is representing Ivy Tech, did not immediately return phone calls or respond to emails.

In another case involving sexual orientation and the federal civil rights law, an employee at Georgia Regional Hospital in Savannah claimed that she was essentially forced out of her security guard job because she is a lesbian. A three-judge panel in the United States Court of Appeals for the 11th Circuit ruled last month that the law did not apply to her.

In a case in New York, an employee at Omnicom Group, a marketing company, said a manager repeatedly taunted him because he is gay. A federal judge dismissed the case, which was appealed to the United States Court of Appeals for the Second Circuit. A three-judge panel ruled last week against the employee, but the chief judge, Robert A. Katzmann, noted that legal and societal views had shifted on legal protections and rights for gay people.

“Other federal courts are also grappling with this question, and it well may be that the Supreme Court will ultimately address it,” he wrote.

Susan Chana Lask, who is representing the employee in the New York case, said she planned to ask for a rehearing before the entire Second Circuit appeals court.

A version of this article appears in print on , on Page A17 of the New York edition with the headline: Civil Rights Act Protects Gay Workers, Federal Appeals Court Rules. Order Reprints | Today’s Paper | Subscribe